Cracked Humbrol Paint and a Sad Beaufort (and a Sad Jeff) - Opinions needed!

[Jeff G]

Feast your eyes upon my weary Beaufort. I brush painted two (newly purchased but seemingly OLD Humbrol paints...!) onto the surface. The paint was so bad - so bad! - but I stayed strong, continually stirring and shaking, etc. to get it to mix and settle. Anyway, I finally got the paint looking...as good as it would get. So I sprayed it with my usual Tamiya TS-80 Flat Clear.

 

And this happened...

 

 

If that's not enough to bring a grown man to tears than I don't know what would (slicing my thumb whilst trimming a part, that's what!). The rest of the paint is fine on the whole aircraft. It's this ONE spot - anyone have any ideas on why? This has happened before and I can't work out a common denominator! I'm thinking I should abandon the TS-80 but I like to give my aircraft a dull coat and I'm unsure what to replace it with - living in Canada I might not have a ton of the usual options. 

 

Thanks in advance,

 

Jeff

[stevehnz]

Hi Jeff, there are probably better qualified than me to come along but as a brush painter, when I want a matt coat, I normally brush on either Vallejo matt varnish or Liquitex matt varnish. I don't use sprays myself but have heard that aerosols can be quite 'hot' & perhaps this causes the reaction, why just in the one place, I can't guess but I do wonder if you've put on too thick a coat which has caused some differential drying & leaves it under stress. Several thin coats seem to work better in that respect. I don't have any problems with brush marks on these varnishes, I use a largish, #6 or 8 decent quality flat brush for applying them & take care to try & finish them along the axis of flight of the aircraft where possible.  Hopefully others will follow.

Steve.

PS, some more info on another thread with similar issues.

[Tbolt]

I believe the TS paints are lacquer based so when spraying onto enamels need to be done in light coats otherwise they will attack the paint and like Steve says light coats are not easy from a spray can. It looks like it has started to happen on the left wing aswell. Maybe try and get a aqueous acrylic instead varnish.

 

I gave up buying Humbrol enamels years ago because of the poor quality control. If you want enamels still, try Colour Coats.

 

how long did you let the enamel dry for? One of the problems I've had with Humbrol QC is some tind don't dry correctly and take several days to cure.

[Casey]

I had to give up on Humbrol, both enamels and acrylics,

 

If you live in Canada, you should have pretty easy access to either Golden Acrylics or Liquitex - they both provide awesome varnishes. I mix their paints as replacement for Humbrol. I find them to be one of best acrylic paints if you are into mixing.  For me - Golden Fluids are perfect for brush painting.

 

But seriously - even the cheap Liquitex Student paints are better than some hobby Humbrols recently

 

Which is extra sad, I have a lot of good memories about this brand and I really want them to get back on their track somehow!

 

Here are my Humbrol measurements:

 

 

and here are calculated recipes

 

If you are missing some, ask, I may need to update it still with even more paints and I am working on it progresively.

 

 

 

Edited May 31, 2022 by Casey

[Peter Roberts]

Only thing I can think of is that it may have pooled or been a bit heavy there with the clear and reacted with the surface. Did you apply light coats or an overall heavy coat?

[Ngantek]

Arg! Sorry to hear about your issues!

 

Yeah I'd echo what others have said. Lacquer onto enamel is always going to be something that needs to be done with care. I have limited experience, but have found some humbrols react more when lacquer is applied above, and likewise different lacquers of the same brand and line react more or less with the same humbrol underneath. I suspect in all cases, it's really important that the humbrol is fully dry and cured, and that the lacquer is applied sparingly in thin layers.

 

In this instance, I suspect the humbrol wasn't fully dry. The upper (over) layer is going to be thicker and take longer to cure, which will be exacerbated by brush painting (giving a thicker layer) and the wing root (which by virtue of its shape, we no doubt all tend to over paint a little by comparison). The fact that you say it felt like a dodgy batch might also mean it's not curing properly. 

 

 

[Jochen Barett]

19 hours ago, Jeff G said:

Feast your eyes upon my weary Beaufort. I brush painted two (newly purchased but seemingly OLD Humbrol paints...!) onto the surface. The paint was so bad - so bad! - but I stayed strong, continually stirring and shaking, etc. to get it to mix and settle. Anyway, I finally got the paint looking...as good as it would get. So I sprayed it with my usual Tamiya TS-80 Flat Clear.

 

And this happened... +++

Old Humbrol paints are good paints (and most can be "rejuvenated" with a dash of white spirit and some elbow grease), but Tamiya TS-80 is truely "hot".

 

I'm still searching for an English version of the material safety data sheet, but the German one will give English speakers a few clues anyway

 

https://www.tamiya.de/tamiya_en/categories/accessories/colours-and-paints/ts-colours/ts-80-flat-clear-100ml-300085080-en.html

"Downloads", and you will find contents worth being mentioned for health reasons (abbreviated) and I marked the ones (red) that I consider relevant to theoretically cured alkyd resin paint.

The alcohols ("-ol") may be harmfull to alkyd resins after some time, but Aceton (your German will be good enough to understand that one) and the other red ones (the EG-Nr or CAS-Nr will help you googeling them) will be way more harmful to alkyd resin paint:

 

"ABSCHNITT 3 Zusammensetzung/Angaben zu Bestandteilen
x
Dimethylether
EG-Nr. 204-065-8 CAS-Nr. 115-10-6
Anteil 45 - 55 % (aerosole Form)
x
Isobutanol
EG-Nr. 201-148-0 CAS-Nr. 78-83-1
Anteil 20 - < 30 % (nicht-aerosole Form)
x
n-Butylacetat
EG-Nr. 204-658-1 CAS-Nr. 123-86-4
Anteil 15 - < 20 % (nicht-aerosole Form)
x
Isobutylacetat
EG-Nr. 203-745-1 CAS-Nr. 110-19-0
Anteil 10 - < 15 % (nicht-aerosole Form)
x
Butan-2-ol
EG-Nr. 201-158-5 CAS-Nr. 78-92-2
Anteil 10 - < 15 % (nicht-aerosole Form)
x
Aceton
EG-Nr. 200-662-2 CAS-Nr. 67-64-1
Anteil 5 - < 10 % (nicht-aerosole Form)
x
2-Butoxyethanol
EG-Nr. 203-905-0 CAS-Nr. 111-76-2
Anteil 4 - < 5 % (nicht-aerosole Form)
x
Cellulosenitrat
EG-Nr. 603-037-01-3 CAS-Nr. 9004-70-0
Anteil 3 - < 5 % (nicht-aerosole Form)
x
1-Methoxypropyl-2-acetat
EG-Nr. 203-603-9 CAS-Nr. 108-65-6
Anteil 2 - < 5 % (nicht-aerosole Form)
x"

 

So, in case you insist on using TS-80 over alkyd resin paint, do it in very light coats and let the solvents evaporate before putting on the next coat, but it would be better to find a flat coat without the ingredients marked red.

Edited May 31, 2022 by Jochen Barett
embarrassing typos

[Enzo the Magnificent]

Have you tried Winsor & Newton Galleria matt varnish?    It should be readily stocked in art shops.   

[MilneBay]

A similar thing happened to me some years ago when I built the 1/48 Tamiya Meteor as one of the aircraft overpainted with white used at the tail end WW2. I wanted to replicate the effect of the white sprayed over the standard DG/OG scheme. There were a couple of areas on the model where I'd used enamel to detail things prior to spraying, and while these were masked off there was some excess paint outside the masked area. The lacquer spray ate straight into these and the result was that I had to strip the model and start all over again. It turned out OK in the end and oddly a positive side effect was that the efforts to repair the damage resulted in a quite realistic worn appearance to the white paint. But I would have preferred to have achieved that effect without all the labour of paint stripping. The Tamiya lacquer paint is hard if not impossible to strip once it cures.

[mike romeo]

Would a brushed layer of klear over the enamel not act as a barrier?

[JWM]

The simple chemical agent which removes any kind of paint from plastic surfaces is NaOH (or KOH) - the main and sometimes the only component of a stuff you use for the unblocking the drain. It is harmful for metals (PE parts are in risk) and for skin. Be careful using it. You may apply this very carefully as solution (perhaps apply it locally using a plastic sponge soaked with it.)  After a couple of hours the paint will be removed.

Regards

J-W

 

[Hook]

On 5/31/2022 at 5:31 AM, Tbolt said:

I gave up buying Humbrol enamels years ago because of the poor quality control.

This.

 

Cheers,

 

Andre

[Seahawk]

On 5/31/2022 at 4:31 AM, Tbolt said:

I gave up buying Humbrol enamels years ago because of the poor quality control.

 

Yes, I wouldn't trust any Humbrol enamel produced this century.  Ancient Humbrol still good to excellent.

[Ed Russell]

Just dunk it in Easy Lift Off and scrub it clean or bin it along with the Humbrol paint and the flat clear and start again.

There's a paint section on Britmodeller which will give you more advice about compatibility of different brands.

https://www.britmodeller.com/forums/index.php?/forum/16-paint/

[Rabbit Leader]

Jeff, I think the issue is the hot Tamiya Lacquer Spray Clear, rather than the Humbrol Enamel paint underneath (although you did state you had problems with this). Many years ago I read something that has stuck with me forever and that easily described what types of paint / thinner mediums should or can be applied over the other and in what preferred order. Put simply it goes something like this: 

 

Lacquer paints are the hardest (Hottest) paint mediums so apply these types of paints first (I still use a good lacquer based primer like Mr. Surfacer). 

Enamels can be applied over the Lacquer without risking any adverse reaction. 

Acrylics can be applied over Enamels (as well as Lacquers) without risking any adverse reaction. 

 

Applying these paint mediums in the opposite way (.i.e. Acrylics, then Enamels, then Lacquers) ‘may’ cause some type of chemical reaction and I believe this is what’s happened in your case. I always try to stick to one paint medium as much as possible during any single build, although have used all three mediums before without encountering any issues. My latest trend is to use Lacquer paints for the top colours and clear coat with acrylics, however once the clear coat is applied I wont go anywhere near enamels or lacquers for fear of reaction.

 

Now I’m sure many of us have had success mixing and matching many different types of paints, but following this simple rule should limit your reaction issues  and convert a Sad Jeff into a happier Jeff. 

 

Cheers and best of luck.. Dave 

 

 

 

 

[stevehnz]

Fwiw,  I mainly use Humbrol, simply because it is the easiest to come by. I have Model Master & Tamiya enamels as well, they're nice to use but not totally without short comings. I will say though that the latest production Humbrol that we get out here is excellent to use, covers well, stays in solution for days & is a good consistency to brush without thinning, though I normally do thin a little, which helps coverage, I do this with Tamiya too. Over that I use mainly Liquitex or Vallejo matt Varnish & sometimes mix both with Klear for a more satin finish. I will agree that early 2000s Humbrol was not that flash at times. That era appears to be well & truly past now production is in the UK again. I just wish they'd bring back some of the more useful targeted shades, rather than the at time seeming random spread of colours they have.

Steve.

[Casey]

16 minutes ago, stevehnz said:

Fwiw,  I mainly use Humbrol, simply because it is the easiest to come by. I have Model Master & Tamiya enamels as well, they're nice to use but not totally without short comings. I will say though that the latest production Humbrol that we get out here is excellent to use, covers well, stays in solution for days & is a good consistency to brush without thinning, though I normally do thin a little, which helps coverage, I do this with Tamiya too. Over that I use mainly Liquitex or Vallejo matt Varnish & sometimes mix both with Klear for a more satin finish. I will agree that early 2000s Humbrol was not that flash at times. That era appears to be well & truly past now production is in the UK again. I just wish they'd bring back some of the more useful targeted shades, rather than the at time seeming random spread of colours they have.

Steve.

Did you use enamels only or also their acrylics?

[stevehnz]

2 minutes ago, Casey said:

Did you use enamels only or also their acrylics?

Enamels only Casey, I have a few Humbrol, Vallejo & Tamiya acrylics but just find the enamels easier to use & as a brush painter, the fume thing is not an issue.

Steve.